Vehicles include a wide variety of adjustable components. Examples include lumbar supports, side supports or other adjustable supports as well as massage units which can be provided in seats to enhance an occupant's comfort when seated on the seat. Lumbar support devices are provided in backrests in order to provide adequate support in the lumbar vertebral or lordosis region of a person sitting on the seat by forming a suitable support surface. Side supports are provided on a backrest and/or on a seat portion to provide adjustable side support. The latter may be desirable not only to accommodate varying occupant sizes, but also to actively adjust lateral support in response to centrifugal forces. Massage units may be integrated into a seat to stimulate blood circulation and/or to further enhance occupant comfort.
Some implementations of adjusting devices for vehicles use one or plural inflatable fluid chambers. The fluid chambers may be configured as inflatable cushions or bladders which change their shape and/or size in dependence on an amount of fluid contained therein. Examples for seats having lumbar support devices implemented using inflatable fluid chambers are described in EP 1 072 465 A1 or in DE 100 63 478 A1. An adjustment of the adjustable support may be effected by means of a pressure source and a suitably configured pneumatic circuit comprising valves and connecting members, such as tubes. While pneumatic elements, such as valves, may enhance life time of and/or comfort provided by the adjustable support device, such components may add to installation space and cost. EP 2 361 800 A1 describes a seat adjusting device which uses a pump with integrated valves.
In addition to installation space and cost, versatility of components used in a pneumatic adjusting device is of importance. For illustration, depending on design constraints or for other technical reasons, it may be desirable to use a pump which can be easily configured for use with a valve module which includes normally open (NO) valves. In this case, the pump should have a design which prevents leakage from inflatable chambers towards a working chamber of the pump, while still being configured for use with a wide variety of valve modules.